DESCRIPTION (Applicant's Abstract): Nucleic acid testing procedures for genotyping of viral pathogens provide results that are utilized in the diagnosis and treatment of diseases such as hepatitis and AIDS. Medical products that directly measure these genetic variants currently utilize internal standards developed by the test manufacturers. The need exists for third party genotyping standards that offer common units of measure and provide testing laboratories with independent methods for ensuring accuracy, reproducibility and consistency in their test procedures. During Phase I, clinical specimens representing the major genotypes of hepatitis B virus (HBV genotypes A - F) and hepatitis C virus (HCV genotypes 1 - 6) will be obtained for calibration against World Health Organization International Standards for these virus nucleic acids, and evaluated for use as potential genotype standards using a variety of commercially available genotyping systems. During Phase II of this project, these materials will be further developed into viral and molecular (cloned DNA or RNA transcripts) standards for HBV and HCV genotyping. The HBV product will be further expanded to include standards for antiviral drug resistance mutations in this virus. All viral and molecular standards will be made commercially available during Phase Ill. PROPOSED COMMERCIAL APPLICATION: This research will lead to the development and commercialization of viral and molecular standards for HBV and HCV genotyping, including HBV drug resistance mutations. Such standardization, currently being implemented for viral load testing, is sorely needed for genotype testing, will facilitate the acceptance of common units of measure for assessing viral genotypes, and will help ensure that genotyping results obtained from multiple laboratories using a variety of test systems throughout the world are accurate, reproducible, consistent and high quality. Commercial manufacturers of genotype assays have expressed a need for independent genotype standards.